Milling is the machining process of using rotary cutters to remove material from a workpiece advancing or feeding in a direction at an angle with the axis of the tool. It covers a wide variety of different operations and machines, on scales from small individual parts to large, heavy-duty gang milling operations. It is one of the most commonly used processes in industry and machine shops today for machining parts to precise sizes and shapes.
Milling can be done with a wide range of machine tools. The original class of machine tools for milling was the milling machine which is often called “a mill”. After the advent of computer numerical control (CNC), milling machines evolved into machining centers which are milling machines with automatic tool changers, tool magazines or carousels, CNC control, coolant systems, and enclosures), generally classified as vertical machining centers (VMCs) and horizontal machining centers (HMCs).